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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Active Palladium Structures on Ceria Obtained by Tuning Pd–Pd Distance for Efficient Methane Combustion

Efficiently removing/converting methane via methane combustion imposes challenges on catalyst design: how to design local structures of a catalytic site so that it has both high intrinsic activity and atomic efficiency? By manipulating the atomic distance of isolated Pd atoms, herein we show that the intrinsic activity of Pd catalysts can be significantly improved for methane combustion via a stable Pd 2 structure on a ceria nanorod support. Guided by theory and confirmed by experiment, we find that the turnover frequency (TOF) of the Pd 2 structure with the Pd–Pd distance of 2.99 Å is higher than that of the Pd 2 structure with the Pd–Pd distance of 2.75 Å; at least 26 times that of ceria supported Pd single atoms and 4 times that of ceria supported PdO nanoparticles. The high intrinsic activity of the 2.99 Å Pd–Pd structure is attributed to the conductive local redox environment from the two O atoms bridging the two Pd 2+ ions, which facilitates both methane adsorption and activation as well as the production of water and carbon dioxide during the methane oxidation process. In conclusion, this work highlights the sensitivity of catalytic behavior on the local structure of active sites and the fine-tuning of the metal–metal distance enabled by a support local environment for guiding the design of efficient catalysts for reactions that highly rely on Pt-group metals.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdF2 by Materials Project

PdF2 is Hydrophilite structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Pd2+ is bonded to six equivalent F1- atoms to form a mixture of corner and edge-sharing PdF6 octahedra. The corner-sharing octahedral tilt angles are 52°. There are two shorter (2.13 Å) and four longer (2.22 Å) Pd–F bond lengths. F1- is bonded in a trigonal planar geometry to three equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SbPd by Materials Project

PdSb is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pd2+ is bonded to six equivalent Sb2- atoms to form a mixture of face, edge, and corner-sharing PdSb6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Pd–Sb bond lengths are 2.78 Å. Sb2- is bonded in a 6-coordinate geometry to six equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdF2 by Materials Project

PdF2 crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. Pd2+ is bonded to six equivalent F1- atoms to form corner-sharing PdF6 octahedra. The corner-sharing octahedral tilt angles are 60°. All Pd–F bond lengths are 2.19 Å. F1- is bonded in a trigonal planar geometry to three equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TePdI by Materials Project

PdTeI crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. Pd2+ is bonded to four equivalent Te1- and two equivalent I1- atoms to form a mixture of corner and edge-sharing PdTe4I2 octahedra. The corner-sharing octahedral tilt angles are 13°. There are two shorter (2.64 Å) and two longer (2.87 Å) Pd–Te bond lengths. Both Pd–I bond lengths are 2.77 Å. Te1- is bonded in a distorted see-saw-like geometry to four equivalent Pd2+ atoms. I1- is bonded in an L-shaped geometry to two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TePd by Materials Project

PdTe is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pd2+ is bonded to six equivalent Te2- atoms to form a mixture of edge, face, and corner-sharing PdTe6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Pd–Te bond lengths are 2.82 Å. Te2- is bonded in a 6-coordinate geometry to six equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdO by Materials Project

PdO is Tetraauricupride structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Pd2+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Pd–O bond lengths are 2.44 Å. O2- is bonded in a body-centered cubic geometry to eight equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdN by Materials Project

PdN is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pd2+ is bonded in a body-centered cubic geometry to eight equivalent N2- atoms. All Pd–N bond lengths are 2.41 Å. N2- is bonded in a body-centered cubic geometry to eight equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SbTePd2 by Materials Project

Pd2SbTe is Caswellsilverite-like structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Pd2+ is bonded to three equivalent Sb2- and three equivalent Te2- atoms to form a mixture of edge, face, and corner-sharing PdSb3Te3 octahedra. The corner-sharing octahedral tilt angles are 51°. All Pd–Sb bond lengths are 2.80 Å. All Pd–Te bond lengths are 2.82 Å. Sb2- is bonded in a 6-coordinate geometry to six equivalent Pd2+ atoms. Te2- is bonded in a 6-coordinate geometry to six equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdSO4 by Materials Project

PdSO4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Pd2+ is bonded in a square co-planar geometry to four O2- atoms. All Pd–O bond lengths are 2.05 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. All S–O bond lengths are 1.50 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Pd2+ and one S6+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Pd2+ and one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdPbF4 by Materials Project

PdPbF4 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Pd2+ is bonded in a square co-planar geometry to four equivalent F1- atoms. All Pd–F bond lengths are 2.02 Å. Pb2+ is bonded in a 8-coordinate geometry to eight equivalent F1- atoms. All Pb–F bond lengths are 2.58 Å. F1- is bonded in a distorted trigonal planar geometry to one Pd2+ and two equivalent Pb2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pd2Cl2O by Materials Project

Pd2OCl2 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Pd2+ is bonded in a square co-planar geometry to two equivalent O2- and two equivalent Cl1- atoms. Both Pd–O bond lengths are 2.05 Å. Both Pd–Cl bond lengths are 2.35 Å. O2- is bonded to four equivalent Pd2+ atoms to form corner-sharing OPd4 tetrahedra. Cl1- is bonded in an L-shaped geometry to two equivalent Pd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl2PdSe2 by Materials Project

PdTl2Se2 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Pd2+ is bonded to two equivalent Tl1+ and four equivalent Se2- atoms to form edge-sharing PdTl2Se4 octahedra. Both Pd–Tl bond lengths are 3.00 Å. All Pd–Se bond lengths are 2.52 Å. Tl1+ is bonded in a 5-coordinate geometry to one Pd2+ and four equivalent Se2- atoms. There are two shorter (3.32 Å) and two longer (3.34 Å) Tl–Se bond lengths. Se2- is bonded in a 6-coordinate geometry to two equivalent Pd2+ and four equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlPdF3 by Materials Project

PdTlF3 is (Cubic) Perovskite structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. Pd2+ is bonded to six F1- atoms to form PdF6 octahedra that share corners with six equivalent PdF6 octahedra and faces with eight equivalent TlF12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Pd–F bond lengths are 2.18 Å. Tl1+ is bonded to twelve F1- atoms to form TlF12 cuboctahedra that share corners with twelve equivalent TlF12 cuboctahedra, faces with six equivalent TlF12 cuboctahedra, and faces with eight equivalent PdF6 octahedra. There are a spread of Tl–F bond distances ranging from 3.04–3.13 Å. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted linear geometry to two equivalent Pd2+ and four equivalent Tl1+ atoms. In the second F1- site, F1- is bonded in a distorted linear geometry to two equivalent Pd2+ and four equivalent Tl1+ atoms. In the third F1- site, F1- is bonded in a distorted linear geometry to two equivalent Pd2+ and four equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GePdO3 by Materials Project

PdGeO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pd2+ is bonded to twelve equivalent O2- atoms to form PdO12 cuboctahedra that share corners with twelve equivalent PdO12 cuboctahedra, faces with six equivalent PdO12 cuboctahedra, and faces with eight equivalent GeO6 octahedra. All Pd–O bond lengths are 2.66 Å. Ge4+ is bonded to six equivalent O2- atoms to form GeO6 octahedra that share corners with six equivalent GeO6 octahedra and faces with eight equivalent PdO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ge–O bond lengths are 1.88 Å. O2- is bonded in a distorted linear geometry to four equivalent Pd2+ and two equivalent Ge4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiPPd by Materials Project

PdNiP crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pd2+ is bonded to five P3- atoms to form distorted PdP5 trigonal bipyramids that share corners with six equivalent NiP4 tetrahedra, corners with ten equivalent PdP5 trigonal bipyramids, edges with six equivalent NiP4 tetrahedra, and edges with six equivalent PdP5 trigonal bipyramids. There are one shorter (2.44 Å) and four longer (2.58 Å) Pd–P bond lengths. Ni1+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with ten equivalent NiP4 tetrahedra, corners with six equivalent PdP5 trigonal bipyramids, edges with two equivalent NiP4 tetrahedra, and edges with six equivalent PdP5 trigonal bipyramids. There are two shorter (2.29 Å) and two longer (2.38 Å) Ni–P bond lengths. There are two inequivalent P3- sites. In the first P3- site, P3- is bonded in a distorted trigonal planar geometry to six equivalent Pd2+ and three equivalent Ni1+ atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to three equivalent Pd2+ and six equivalent Ni1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiNiPd by Materials Project

PdNiSi crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Pd2+ is bonded to five Si4- atoms to form distorted PdSi5 trigonal bipyramids that share corners with six equivalent NiSi4 tetrahedra, corners with ten equivalent PdSi5 trigonal bipyramids, edges with six equivalent NiSi4 tetrahedra, and edges with six equivalent PdSi5 trigonal bipyramids. There are one shorter (2.45 Å) and four longer (2.56 Å) Pd–Si bond lengths. Ni2+ is bonded to four Si4- atoms to form NiSi4 tetrahedra that share corners with ten equivalent NiSi4 tetrahedra, corners with six equivalent PdSi5 trigonal bipyramids, edges with two equivalent NiSi4 tetrahedra, and edges with six equivalent PdSi5 trigonal bipyramids. All Ni–Si bond lengths are 2.33 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to six equivalent Pd2+ and three equivalent Ni2+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to three equivalent Pd2+ and six equivalent Ni2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HgPdF4 by Materials Project

PdHgF4 is Hydrophilite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pd2+ is bonded to six F1- atoms to form PdF6 octahedra that share corners with four equivalent PdF6 octahedra and corners with eight equivalent HgF6 octahedra. The corner-sharing octahedra tilt angles range from 56–63°. There are a spread of Pd–F bond distances ranging from 2.20–2.24 Å. Hg2+ is bonded to six F1- atoms to form HgF6 octahedra that share corners with four equivalent HgF6 octahedra and corners with eight equivalent PdF6 octahedra. The corner-sharing octahedra tilt angles range from 57–64°. There are a spread of Hg–F bond distances ranging from 2.31–2.39 Å. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a trigonal planar geometry to two equivalent Pd2+ and one Hg2+ atom. In the second F1- site, F1- is bonded in a trigonal planar geometry to one Pd2+ and two equivalent Hg2+ atoms.

36 MATERIALS SCIENCE↗